Ice damage prevention



Jan. 1955 H. w. HOSFORD, JR 2,700,649

ICE DAMAGE PREVENTION Filed July 14, 1951 INVENTOR. HHPRY M HOFQRD, JR.

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United States Patent "Ofi ice 2,700,649 P atented Jan. 25, 1955 ICE DAMAGE PREVENTION Harry W. Hosford, Jr., Shaker Heights, Ohio Application July 14, 1951, Serial No. 236,838

Claims. (Cl. 204-496) This invention relates as indicated to ice damage prevention and more particularly to means for preventing ice damage to a member suspended in a freezable liquid.

Elongated anodes which may be of aluminum or graphite, for example, are commonly suspended 1n large steel water tanks to prevent corrosion of the latter, a proper voltage being maintained to prevent solution of the iron. The anodes, of course, gradually disintegrate. Such anodes are generally in the form of long rods or bars suspended from thereof of the tank and are qulte heavy, and in the case of graphite also rather fragile.

A serious problem has been encountered due to freezing of water in the tanks in the wintertime. Thus, a layer of ice six inches or a foot thick may freeze at the surface of the water, adhering to the sides of the tank and to the anodes suspended therein. Ordinarily, the number of anodes employed may range from seven to sixteen depending on the size of the tank. When water is now withdrawn from the tank, this layer of ice will remain unsupported until it eventually collapses. When the ice comes down, it invariably rips the anodes loose despite all precautions to prevent this. Stainless steel anodes have even been known to be driven through the bottom of a tank by the weight of ice adhering thereto. Attempts have been made to suspend the anodes from floats and otherwise to support the same to render them less susceptible to ice damage. Due to a combination of mechanical and electrical problems, however, no solution has previously been found, and it is customary practice to remove the anodes from the tanks each fall and to reinstall the same in the spring, permitting the tanks to corrode during the winter months.

A primary object of this invetnion is accordingly to provide means for preventing ice damage to a member suspended in a freezable liquid and more specifically to prevent such member from being ripped from its mooring when a surface layer of ice formed on such body of liquid subsequently collapses.

A further object is to provide a suspended electrode and guard assembly which will prevent ice from exerting a sufficient pull on the electrode to detach the same.

Other objects and advantages of the present invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. 1 is a view in side elevation of a steel water tank suitable as a reservoir for a municipal water supply, for example;

Fig. 2 is an enlarged fragmentary vertical cross-sectional view of such tank showing a plurality of elongated electrodes suspended in water therewithin, in accordance with the present invention;

Fig. 3 is an enlarged detail view, partly in section, of one such electrode shown encircled by a novel float member of my invention and surrounded by a layer of ice; and

Fig. 4 is a wiring diagram of an electric circuit including the electrodes whereby corrosion of the tank is prevented.

Referring now to the drawing and more particularly to Figs. 1 and 2, there is there shown an ordinary water tank or tower, generally indicated at 1, having a riser 2 in communication therewith which serves to conduct to and/or from the tank the liquid with which the latter is filled. The tank is shown supported by legs 3. As indicated above, elongated anodes of aluminum or graphite, for example, are commonly suspended in steel water tanks in order to prevent corrosion of the latter.

In the drawing, such anodes are shown in the common form of elongated rods or bars 4 which are suspended from the roof of the tank by means of electric submarine cables 5. As will be seen, such cables are suspended from eye bolts 6 secured at spaced intervals about the roof of tank 1. A second set of eye bolts 7 threadedly engaged in the upper end of each electrode 4 are secured to the lower end of respective cables 5. Usually from seven to sixteen of these electrodes will be employed and maintained with a positive charge so as to serve as anodes, such anodes being desirably uniformly spaced within the tank to afford complete protection to the entire inner surface thereof.

In Fig. 4 is a transformer 8 for obtaining variable secondary voltages from tap switches 9. Lines from the tap switches are connected to the full wave rectifier 10 which changes the alternating current supply to a pulsating direct current. Such rectifier is enclosed in a box 11 shown attached to a leg of the water tower with the positive and negative lines 12 and 13 of the rectifier leading therefrom and enclosed within a conduit 14 secured to the same leg of the tower and extending to the junction box 15 secured to the roof of the tank. Cables 5 extend in loops 16 to junction box 15 and connect with the positive line 12 of the rectifier. The free ends of the cables have thereon wire lugs 17 held against the upper ends of the respective anodes 4 by hex-nuts 18 threaded on eye bolts 7.

At 19 and 20, the negative lead 13 from the rectifier makes electrical contact with the tank, and a proper voltage is maintained in the circuit including the rectifier, tank, water and bars to prevent solution of the iron of the tank.

Openings 21 formed in the roof of tank 1 adjacent the respective eye bolts 6 provide easy access to the electrodes 4 for adjustment or repair. Such openings are capped by covers 22 secured in place by means of a threaded bolt connection with transverse bars 23 disposed loosely within the tank. It will thus be seen that each electrode is suspended from the top of the tank merely by the electric cable connected thereto. The employment of much heavier supporting means has been tried to reduce ice damage but with very unsatisfactory results. The great weight of ice which may accumulate, when it suddenly collapes, is capable of wrenching loose very strong mountings with resultant damage both to the top of the tank and to the bottom thereof where struck by the electrodes. Moreover, such heavy mounting means are relatively expensive and inconvenient. To protect the tank against corrosion the electrodes must be properly arranged, with no obstruction of consequence between the same and the walls of the tank. Furthermore, they must not make electrical contact with the tank. For these reasons it is not feasible to provide special braces and the like to assist in supporting the electrodes.

In accordance with the present invention, a resiliently deformable annular ring 24 preferably of rubber or other plastic material is provided floated closely about each electrode, such rings of course rising and falling with the change in the level of the water in the tank. As illustrated, such rings may for example comprise an inner structure formed of a number of tubes 25 within an outer flexible water-proof sleeve 26. Alternatively such rings may merely comprise a flexible inflated tube. It is important, however, that the rings float in the liquid in the tank and have a degree of flexibility. The rings should be of a shape which will not tend to be forced upwardly when ice freezes thereabout, and ordinarily approximately 70% of each ring should normally float submerged.

When a layer of ice 27 formed on the surface of the water within the tank and adhering to the walls of the latter, collapses following a drop in the water level to a point indicated at 28 for example, instead of dragging the electrodes with it the rings will serve the function of a flexible yielding connection, breaking up the ice thereabout and causing chunks of the same to pivot and collapse in the manner shown at 29. Furthermore, the flexibility and stretchability of the rings serve to lessen the shock to electrodes 4 as the ice collapses and pulls away from such rings. The remaining layers of ice 30 confined between the electrodes and their respective rings are of course not heavy enough to pull such electrodes loose from their supporting cables.

My flexible floating ring guard should be of a relatively short axial dimension relative to the anode it surrounds so as not to obstruct the latter unduly. The inner diameter of the ring should be suflicient to ensure free rise and fall of the ring with changes in the level of the water and the ring itself should be of material capable of accommodating repeated freezing in the surface ice without damage thereto. A float of rigid construction is much less suitable in that it fails to afford the resilient hinge effect I obtain with my ring of flexible material. Such rings, when used in conjunction with anodes as described, should in any case be of non-metallic material at their outer surface not to interfere with the function of the anodes. Since the rings are preferably weighted to float with a major proportion submerged, the tendency to force the same upward during freezing is much reduced. Such rings may be made with a constricted or dumbbell cross-section similarly to assist in preventing such upward movement.

While the present invention is particularly useful in protecting anodes employed to prevent water tank corrosion it will be understood that this use of the invention is by way of illustration only and that the invention may be employed to advantage in the protection of any member suspended in a body of liquid where such liquid is subjected to freezing temperatures and subsequently withdrawn so as to leave an unsupported layer of ice adhering to the member and subject to eventual collapse.

While as indicated above it will generally be highly desirable that the ring be both flexible and capable of floating in the liquid, it will also be of service even in certain special instances where the water level is always maintained constant, as in the case of tanks serving as fire main supply. Thus, when the water freezes, the resiliently deformable and compressible ring will yield, preventing pressure damage to certain of the more fragile types of electrodes. In this type of installation the ring may be suspended or otherwise supported instead of floated on the surface of the water since the level of the latter will be constant.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a metal water tank having an elongated electrode suspended vertically and extending down a substantial distance therein, said tank having inner corrodible surfaces and said electrode being of the type adapted to prevent corrosion of such tank, a small annular float of flexible material closely encircling said electrode but having an inner diameter substantially greater than the outer diameter of said electrode and adapted to rise and fall freely relative thereto with changes in the liquid level, said float having a specific gravity of such magnitude as to float normally in water with a major portion submerged, whereby upon freezing of a surface layer of such water and subsequent collapse of such layer due to withdrawal of water therebeneath said float will act as a flexible yielding connection with the ice adhered thereto and thereby lessen the shock imposed on said electrode.

2. A construction as set forth in claim 1 wherein means are provided to maintain a positive charge of electricity on such electrode and a negative charge on said tank.

3. A construction as set forth in claim 1 wherein said annular float comprises a plurality of inflated tubes and a flexible water proof sleeve enclosing said tubes.

4. A construction as set forth in claim 1 wherein each half of the cross section of the annular float is dumbbell shaped with the ends of said dumb-bell vertically disposed.

5. In a method of protecting a metallic Water tank against corrosion with an elongated depending protective electrode, the step of preventing ice damage comprising surrounding said electrode with a yielding float while maintaining the major portion of said float submerged and permitting free movement between the float and electrode.

Frazier Jan. 17, 1911 Clififord Nov. 27, 1917 

1. IN A METAL WATER TANK HAVING AN ELONGATED ELECTRODE SUSPENDED VERTICALLY AND EXTENDING DOWN A SUBSTANTIALLY DISTANCE THEREIN, SAID TANK HAVING INNER CORRODIBLE SURFACES AND SAID ELECTRODE BEING OF THE TYPE ADAPTED TO PREVENT CORROSION OF SUCH TANK, A SMALL ANNULAR FLOAT OF FLEXIBLE MATERIAL CLOSELY ENCIRCLING SAID ELECTRODE BUT HAVING AN INNER DIAMETER SUBSTANTIALLY GREATER THAN THE OUTER DIAMETER OF SAID ELECTRODE AND ADAPTED TO RISE AND FALL FREELY RELATIVE THERETO WITH CHANGES IN THE LIQUID LEVEL, SAID FLOAT HAVING A SPECIFIC GRAVITY OF SUCH MAGNITUDE AS TO FLOAT NORMALLY IN WATER WITH A MAJOR PORTION SUBMERGED, WHEREBY UPON FREEZING OF A SURFACE LAYER OF SUCH WATER AND SUBSEQUENT COLLAPSE OF SUCH LAYER DUE TO WITHDRAWAL OF WATER THEREBENEATH SAID FLOAT WILL ACT AS A FLEXIBLE YIELDING CONNECTION WITH THE ICE ADHERED THERETO AND THEREBY LESSEN THE SHOCK IMPOSED ON SAID ELECTRODE. 